1. Field of the Invention
This invention relates to colorants. More particularly, it concerns a family of red colorants which per se and as lakes find special application as red colorants for edibles and cosmetics.
2. The Prior Art
FD&C Red #2, a monoazo dye of the formula ##STR2## commonly known as Amaranth, was among the most widely used colors in foods, drugs and cosmetics. In 1975 these uses were prohibited in the United States when the Food and Drug Administration ruled that the dye's safety was questionable. The removal from commerce of this compound has left a great need. Edibles such as cherry, raspberry, and strawberry-flavored gelatin desserts, beverages, candies and jams, and nonedibles such as inks and dyes were formulated around the particular tint and hue of this color. Several replacement colors have been proposed but have not been fully acceptable. For example, FD&C Red #40, another monoazo dye which has the formula ##STR3## and which is disclosed in U.S. Pat. No. 3,640,733, issued Feb. 8, 1972 to Rast et al., is now being used as a replacement. This material has a brownish cast which interferes with many uses. Natural colors, such as are extracted from beets, have been suggested as well but have low coloring power, and thus unacceptably high costs in use. The present invention seeks to provide a replacement for now-delisted azo color Red #2. This invention discloses a limited family of new anthraquinone colorants which are excellent color matches for Red #2. The colorants of this invention can take on two forms. They can be monomeric, as have been all food colors approved for use heretofore. Preferably, however, these new colors are in polymeric form. As is disclosed in U.S. Pat. No. 3,920,855, issued Nov. 18, 1975 to Dawson et al., in copending United States patent application Ser. No. 520,530, filed Nov. 4, 1975 by Gless et al., now U.S. Pat. No. Re. 30,362 and in Japanese patent applications of Tanabe, such as Nos. 41-14433, 41 -14434 and 44-13382, having colors in polymeric form can be advantageous. When polymeric colors are used in edibles, if the size of the molecules of polymeric color exceeds a certain limit--usually a molecular size of from about 1000 to 2000 Daltons--and if the color compounds do not break down and thus maintain this size, the polymeric colors are not absorbed through the walls of the gastrointestinal tract. This means that when such materials are eaten, they essentially pass directly through the gastrointestinal tract. They are not taken into the body or its systemic circulation and thus any risk of possible systemic toxicity is eliminated.